It has previously been proposed to provide an ankle brace or orthopaedic apparatus, including air inflatable bladders as shown in Glenn W. Johnson, Jr.'s U.S. Pat. Nos. 4,280,489,granted July 28, 1981,and No. 4,628,945,granted Dec. 16, 1986in which the apparatus is intended to be worn within a separate shoe and is inflatable with an external source of air pressure or is preinflated. In addition, various arrangements have been proposed for ventilating shoes by circulating air through the shoes. Typical patents showing this type of arrangement include M. Dunker, U.S. Pat. No. 2,552,711;D. W. Oltrogge, U.S. Pat. No. 2,560,591;A. C. Crawford, U.S. Pat. No. 2,676,422;C. N. Eaton, U.S. Pat. No. 3,029,530;E. Karras, U.S. Pat. No. 3,331,146;and James Faiella, U.S. Pat. No. 4,414,760.These patents disclose the use of an air pumping arrangement actuated by foot pressure for circulating air through a shoe, but do not include any orthopaedic support functions. Reference is also made to German publication designated OffenlegungSschrift No.2321817,published Nov. 15, 1973.That publication shows a ski boot with a rigid sole and a pump mounted in the sole. The pump can be latched to an inactive state when the inflatable pads are pressurized.
After injury to an ankle, such as a fracture or severe ankle sprain, it may be necessary to completely immobilize the ankle through the use of a molded plaster or resin cast. However, once the injury has been stabilized, recovery may be hastened by removing the molded plaster or resin cast and using a removable functional walking brace so that the ankle can be exercised during healing. Also, if the injury is not severe enough to require complete immobilization, it may only be necessary to use a functional walking brace to stabilize the ankle against inversion (the foot rolling inward), eversion (the foot rolling outward) or anterior subluxation (partial dislocation) while still permitting the normal dorsiflexion and plantarflexion forward and rearward motion of the lower leg relative to the foot) movement of the ankle. However, less pressure and support is required when resting. Furthermore, it is undesirable to have the feet or ankles subject to substantial pressure while resting as this may inhibit circulation during rest periods.
It is therefore desirable to have an ankle brace which provides greater support and pressure to the ankle during walking and the like and less pressure upon the ankle and foot during periods of rest.